1. Field of the Invention
The present invention relates to an articulate joint to guide a laser beam freely to a desired point in a laser processing machine for use in cutting, welding, heat treating or alloying of metals, plastics and other materials.
2. Description of the Prior Art
FIG. 1 of the accompanying drawings shows a conventional laser processing machine 1 which has articulate joints 2 for freely bending arms 3 to transmit a laser beam to a desired position. As shown in FIGS. 2 and 3, each articulate joint 2 interconnects two hollow arms 3a, 3b mutually bendable in two parallel planes to allow a laser beam to pass through them. One of the arms 3a has a mirror 4a placed in its corner which is coupled to the other arm 3b for reflecting a laser beam from the arm 3a into the arm 3b in the direction of a pivot axis x of the articulate joint 2. The other arm 3b also has a mirror 4b positioned in its corner which is coupled to the arm 3a for reflecting the laser beam as it passes along the pivot axis x to travel in the arm 3b.
The articulate joint 2 in the thus-constructed laser processing machine 1 has a disadvantage because the laser beam is unduly attenuated as it is reflected by the mirrors 4a, 4b.